The objectives of this undertaking are to originate new epidemiologic approaches to the study of cancer causation in man and animals, to develop sources of data related to specific epidemiologic problems, to stimulate epidemiologic research in other health agencies and to develop an on-the-job training program for medical and statistical officers. Opportunities for research in cancer epidemiology are based on questions arising from clinical or laboratory observations, on unusual groupings of cancer cases in the population, and on study of the characteristics of groups of persons prior to the onset of a specific type of cancer as compared with similar persons who have not developed the disease. In parallel with this, plans are made for on-the-job training in cancer epidemiology for research physicians, veterinarians, and statisticians.